Method of constructing the foundations of cellarless houses



May 12, 1942.

H. w. BROWN 2,282,452 METHOD OF GONSTRUGTING THE FOUNDATIONS OF CELLARLESS HOUSES I Filed Oct. 28, 1958 Sheets-Sheet 1 INVENTOR.

J N Am 1942- H. w. BROWN 2 2 2,282,452

METHOD OF CONSTRUC'I'ING THE FOUNDATIONS OF CELLARLESS HOUSES 2Sheets-Sheet 2 I INVENTOR. X}

Patented May 12, 1942 U-NlTED STAT METHOD OF CONSTRUCTING, THEiFQUNDA-TIONS OF CELLARLESS HOUSES 4 Claims.

My invention relates to improvements in the method of laying thefoundation of a cellarless air-conditioned house and to the provision ofducts therein for air conveyance and heat transfer, all to the end ofproducing a structure which will be simple and in large part adapted tothe use of cheap labor and simple tools in its construction. To theseand other ends which will appear, my invention consists in certainimprovements in foundation construction which will first be describedwith reference to the annexed drawings and will then be specificallypointed out in the claims. It is intended that the specific form of theinvention here shown and described shall be illustrative only. It may bemodified in various ways within the limits set by the appended claims.

In the drawings Figs. 1, 2 and 3 show in vertical section one of thefoundation piles or piers for a cellarless house at three successivestages of its construction;

Fig. 4 shows in Vertical section a portion of a completed foundation;

Fig. 5 shows in vertical section the preferred form of air-return trenchhaving a heat economizer in the form of ducts for waste gases ofcombustion in the trench in heat-transfer relation to the air-returnduct;

Fig. 6 is a fragmentary vertical section of the foundation and floortaken at right angles to Fig. 5; and

Fig. 7 is a sectional view similar to Fig. 5 illustrating amodification.

Referring to Figs. 1 to 4, it will be observed that the foundationcomprises several concrete piers or piles l of sufilcient lengthvertically to reach below the frost line and to a satisfactory bearingmaterial, supporting and forming a monolithic structure with a concreteslab 2, whose underside is arched to render the transfer of load to thepiles more eflicient. A pile is made as follows: A hole 3, in the earth,at the corner or at a point along or within the perimeter of the spaceto be occupied by the building, is excavated to the depth just stated,the bottom of the hole being flattened to give good bearing andstability. Concrete is then poured in the bottom of the hole (Fig. 1) togive a substantial pedestal or anchor 4 say six inches in thickness. Theshaft part of the pile is then formed by a method which involves thesaving of concrete by limiting the diameter of the column to what isnecessary, and it is not usually necessary to entirely fill theexcavated hole with concrete in order to secure a pile of, the rightstrength. A steel cylinder 5 is placed, usually centrally, in the hole,and supported by the concrete pedestal 4. Back filling withthe excavatedmaterial and tamping it around the cylinder 5 as at 6, then proceeds asthe interiorof the cylinder is poured with concrete 1 (Fig. 1). As thecylinder is filled it is Withdrawn (Fig. 2|) so that the back fillingremains as av form to hold the concrete shaft in place. Back filling,concrete pouring and withdrawing of the cylinder may be continued untilany desired. length of pile has been made (Fig. 3).

The concrete piles I are spaced to give adequate support for. thestructure to be erected. Where load concentrations occur, as atchimneys, piles are placed directly thereunder.

The main supporting slab 2 is made by first grading the earth underlyingthe intended structure to the form of a series of modified groinedarches 8 (Fig. 3). If the fill is kept low at the top of the piles. andis then sloped to a high point midway between-piles, it will providenaturally efficient arch action in the slab when poured, thereon. (Fig.4), to transfer the loads of and on the slab to the supporting piles.The

slab is poured directly on top of the piles and,

this archedfill. Becauseof. this arching, tensile stresses in theconcrete are largely eliminated, and, consequently, the need for tensilereenforcing is eliminated, or reduced. Furthermore, any settling of fillwhich may have been used above or around the piles, will not aifect thestability of the structure; in fact, the fillcould be excavated afterthe concrete has set, and the structure would be stable, as the earthfill is but a form for the concrete during pouring and setting.

In order to pour the main supporting slab, a form 9 is placed around theperimeter of the space to be occupied by the slab, at the desired level.Most residences-require a width of such extent that an intermediateguide between these outside forms is necessary in order to insure alevel slab, and it is also desirable, in an airconditioned house to havea central return duct or trench l0 tov conduct the return air to theair-conditioning plant. If this return trench is located in a reasonablycentral location, it will serve several purposes while construction isproceeciling besides its permanent function as an air duc First,theforms So for its concrete sides will act as guides additional'tov theforms 9 for the pouring and leveling of the main slab 2. Second, beingof some Width,. it enables the workman to walk in it while leveling themain slab without walking on other recently poured concrete. The slab II(Fig. 4) for the bottom of the airreturn trench is poured whencompleting the pouring of the piles I, viz. on the day previous to thepouring of the main slab '2 so that the,

surface of the slab II is available for use of the workman working onthe main slab. A bar of wood I2 of length enough to span the distancebetween forms 9 and 9a, is used as a straightedge, guided by the upperedges of the forms, in leveling the surface of slab 2.

After the concrete in the main slab has set, the forms 9 and 9a areremoved and the Whole surface of the slab is given a coating ofemulsified asphalt I3 to, (1) seal in the water in the concrete toprovide good curing conditions, (2) prevent moisture from the concreteslab, or the under lying ground from penetrating upward into the house,(3) assist in holding the sleepers to the concrete by virtue of theadhesive qualities of the asphalt. Sleepers I4 (Fig. 5) are next spikedon the emulsified asphalt on top of the slab 2, as may be required forthe walls, partitions, and floor finishing material. If only smallstones, not over one half inch in diameter, are used in the concrete ofthe main slab, and if one waits until the concrete has set to just theproper point, these sleepers may be held in place by driving spikes I5into the relatively green concrete. The proper time, after pouring themain slab, for spiking sleepers to the green concrete depends upon theproportion of cement to aggregates, the size of the aggregates, and thecuring condition. The concrete must be hard enough to hold the spikesfirmly in place but not so hard as to render their drivingimpracticable. Preferably, a second coat of emulsified asphalt I6 isthen applied over the former one in the spaces between the sleepers. Thecombination of the original asphalt coating, the spiking to the greenconcrete, and the second coating with asphalt over the slab between thesleepers, has proved to be an effective method of waterproofing theslab, sealing and supporting the edges of the: sleepers and holding thesleepers in place. It has also been found that sleepers are lessaffected by roughnesses in the concrete surface, have less tendency toroll, and consequently hold better, if they are of approximately squarecross section, i. e., 2" X2" sleepers work better than 2"x3 or 2" x4",and provide equally good nailing for the top or finish fioor 3B.

In order to extract all possible heat from the waste gases flowing fromthe main heating apparatus, hereinafter described, the air-return.trench II] is preferably further developed to actas an economizer byarranging in the lower part thereof a passage II, II, for these wastegases, so that the heat contained in them may be given. up to theconcrete bottom slab I8 of the airreturn trench, and be taken up by theair on its way to the heater. Since these waste gases contain more orless water vapor, depending on the fuel used, provision must be made forthe con-- densation of this vapor; consequently the gas passages in thetrench must be formed by using sidewall blocks I9, which are of burnedclay products or concrete, and the passages must be: pitched to a drainor dry well, not shown, toevacuate condensate, even though much of thecondensate remains in the form of mist. In constructing the economizertrench, it is desirablethat the sides I9 of the waste gas passages bemade of a poor conductor of heat, so that as:

much heat as possible will be given up to the slab IIa instead of beingsomewhat dissipated into the fill under the main slab 2. (This heatwould eventually get to the main slab, but only after a considerableamount of the surrounding fill had been heated enough to cause some flowupward to the slab.) Cinder concrete blocks have been used for the sidewalls IS with satisfactory results. A sheet of cement asbestos board 2|is placed over the members I9 to act as a form for pouring the concreteslab II a and also as an extra precaution against leakage of waste gasesinto the air-return duct I0. Insurance against cracks occurring in slabI Ia at the joints of the sheets of cement asbestos board is provided bythe continuous steel reenforcing bars 22 embeddedin the slab. Since itis often de sirable to operate the main heating apparatus when the airheating apparatus may not be in operation, the specific heat of slab I8should be suflicient to absorb the available heat in the waste gaseswithout causing a serious increase in the temperature of slab i8. Underordinary conditions in a residence it has been found that three inchesthickness for slab I8 accomplishes this result, as well as providing asecure seal against the waste gases passing into the airreturn space.

An alternative method of forming an economizer trench is shown in Fig.7. Here round pipes Ila, Ila of clay or other material are embedded inthe slab III) which forms the bottom of the air duct Ill and which maybe reenforced by steel bars 22 and be poured on top of the piles I asalready described. The pipe is not so advantageous for heat transfer asthe large surface of flat slab I8 for the hottest gases to wipe againstas in the previous method. Also, the pipes surrounded by concrete do nothave the side insulating value of cinder block.

In both illustrative forms of the economizer trench, the waste gaspassage is shown with two compartments, as it is frequently desirable tohave the gases flow from the heater to one end of the house, and thenreturn to a chimney or exhaust at the other end; the two-part passageallows for flow in opposite directions.

I claim: I

l. The improvement in the art of constructing cellarless houses whichconsists in preparing a foundation by first excavating holes for piles,of a width greater than the diameter of the pile and of a depth to reachbelow frost, pouring concrete to cover the bottom of the holes and formpedestals for the piles, placing a thin metal tube as a form on thepedestals, pouring concrete in the tube, back filling around the tubeand withdrawing the tube as the pouring and back filling continue andpouring a concrete slab upon the piles and the earth between them toform a monolithic foundation, comprising concrete piles supported on theearth below frost line and arches of normal, meaning therebynon-inverted, form supported on the piles.

2. A method such as set forth in claim 1 in which after the piles arepoured the work of completing the foundation is proceeded with bypreparing the earth surface between the piles to provide a form in theshape of modified groined arches, pouring a concrete slab over andbetween the piles on the uncompacted fill so that drying, andsettling ofthe fill will leave the slab out of contact with it and transfer theslab load to the piles.

3. The method set forth in claim 1, in which after the concrete haspartly hardened and while it remains in a green state, it is coveredwith emulsified asphalt and sleepers are laid thereon and spiked to thegreen concrete.

4. The method set forth in claim 1, in which after the concrete haspartly hardened and while it remains in a green state it is coveredwith;

emulsified asphalt and sleepers are laid thereon the first after thesleepers are fastened in place to seal and support the edges of thesleepers.

HORATIO WHITTEMORE BROWN.

